Tag Archives: olive oil

Low-Carb Mediterranean Diet Improves Glucose Control and Heart Risk Factors in Overweight Diabetics

In overweight type 2 diabetics, a low-carbohydrate Mediterranean diet improved HDL cholesterol levels and glucose control better than either the standard Mediterranean diet or American Diabetes Association diet, according to Israeli researchers reporting earlier this year.

Background

Prior studies suggest that diets rich in monounsaturated fatty acids (olive oil, for example) elevate HDL cholesterol and reduce LDL cholestrol and triglycerides in type 2 diabetics.

Low-carb diets improve blood sugar levels and reduce excess body weight in type 2 diabetics, leading to the ADA’s allowance in 2008 of a low-carbohydrate diet as an alternative to standard diabetic diets.

Many—probably most—type 2 diabetics have insulin resistance:  the body’s cells that can remove sugar from the bloodstream are not very sensitive to the effect of insulin driving sugar into those cells.  They “resist” insulin’s effect.  Consumption of monounsaturated fatty acids  improves insulin sensitivity.  In other words, insulin is better able to push blood sugar into cells, removing it from the bloodstream.

Previous studies have shown that both low-carb diets and the Mediterranean diet reduce after-meal elevations in blood sugar, which likely lowers levels of triglycerides and LDL cholesterol.

How Was the Study Done?

The goal was to compare effects of three diets in overweight type 2 diabetics in Israel over the course of one year.  Study participants totalled 259.  Average age was 56, average weight 86 kg (189 lb), average hemoglobin A1c 8.3%, and average fasting plasma glucose (sugar) was 10.3 mmol/L (185 mg/dl).  [Many diabetics in the U.S. fit this profile.]  People taking insulin were excluded from the study, as were those with proliferative diabetic retinopathy—no reasons given. 

Participants were randomly assigned to one of three diets, so there were about 85 in each group.  [Over the course of one year, people dropped out of the study for various reasons, leaving each group with about 60 subjects.] 

Here are the diets:

  • 2003 ADA (American Diabetes Association) diet:  50-55% of total caloric intake from carbohydrate (mixed glycemic index carbs), 30%  from fat, 20% from protein
  • Traditional Mediterranean (TM):  50-55% low-glycemic-index carbs, 30% fat—high in monounsaturated fat, 15-20% protein
  • Low-carb Mediterranean (LCM) :  35% low-glycemic-index carbs, 45% fat—high in monounsaturated fat, 15-20% protein

Patients were followed-up by the same dietitian every two weeks for one year.  All were advised to do aerobic exercise for 30-45 minutes at least three days a week.

Olive oil is traditionally the predominant form of fat in the Mediterranean diet and is a particularly rich source of monounsaturated fat.  At no point in this report was olive oil mentioned, nor any other source of monounsaturated fat.  Until I hear otherwise, I will assume that olive oil was the major source of monounsaturated fat in the TM and LCM diets. 

 All diets were designed to provide 20 calories per kilogram of body weight. 

In all three diets, saturated fat provided 7% of total calories.  Monounsaturated fatty acids provided 23% of total calories in the LCM, and  10% in the other two diets.  Polyunsaturated fatty acids provided 15% of calories in the LCM, and 12% in the other two diets.  The ADA diet provided 15 grams of fiber, the TM had 30 g, and the LCM had 45 g.

Adherence to the assigned diet was assessed with a “food frequency questionnaire” administered at six months.

What Did the Researchers Find?

Average reported energy intake was similar in all three groups: 2,222 calories per day.

Monounsaturated fat intake differences were statistically significant: 14.6, 12.8, and 12.6% for the LCM, TM, and ADA diets, respectively.  Polyunsaturated fat intake differences were statistically significant: 12.9, 11.5, and 11.2% for the LCM, TM, and ADA diets, respectively.

Percentage of energy from carbs was highest for the ADA diet (45.4%), intermediate for the TM diet (45.2%), and lowest for the LCM diet (41.9%).

At the end of 12 months, all three groups lost about the same amount of weight (8-9 kg or 18-20 lb), body mass index, and waist circumference.

Hemoglobin A1c fell in all three groups, but was significantly greater for the LCM group than for the ADA diet (6.3% absolute value vs 6.7%).

Triglycerides fell in all three groups, but was significantly greater for the LCM diet compared to the ADA diet.

The LCM group achieved a significant increase (12%) in HDL cholesterol compared to the ADA diet, but not different from the TM group.

LDL cholesterol fell in all three groups, and the LCM group’s drop (25%) was clearly superior to that of the ADA diet (14%) but about the same as the TM diet (21%).

Conclusions of the Investigators

We found that an intensive community-based dietary intervention reduced cardiovascular risk factors in overweight patients with [type 2 diabetes] for all three diets.  The LCM group had improved cardiovascular risk factors compared to either the ADA or the TM groups.

Only the LCM improved HDL levels and was superior to both the ADA and TM in improving glycaemic control.

It would appear that the low carbohydrate Mediterranean diet should be recommended for overweight diabetic patients.

My Comments

There’s no way the average diabetic could replicate this low-carb Mediterranean diet without working closely with a dietitian or nutritionist.

Any superiority of this low-carb Mediterranean diet may have as much to do with the increased monounsaturated fat intake as with the reduced carb consumption.  Monounsaturated fatty acid consumption is thought to improve insulin sensitivity. 

NutritionData’s Nutrient Search Tool can give you a list of foods high in monounsaturated fat.

The Mediterranean diet and low-carb diets independently have been shown to lower after-meal glucose levels, which probably lowers LDL cholesterol and triglycerides.

I’m disappointed the dietitians were not able to achieve a lower level of carbohydrate consumption in the low-carb Mediterranean diet group.  I suspect if they had, improvements in glucose control and lipids would have been even better.  But proof awaits another day.

We saw last year an article in the Annals of Internal Medicine that showed a dramatic reduction in the need for glucose-lowering drugs in type 2 diabetics following a different low-carb Mediterranean diet over four years, compared to a low-fat American Heart Association diet.  These two studies convince me a low-carb Mediterranean diet has real life-preserving and life-enhancing potential. 

Diabetics looking for a low-carb Mediterranean diet today have several options:

If you’re aware of any other low-carb, explicitly Mediterranean-style diets, please share in the Comments section.

Steve Parker, M.D. 

References: 

Elhayany, A., Lustman, A., Abel, R., Attal-Singer, J., and Vinker, S.  A low carbohydrate Mediterranean diet improves cardiovascular risk factors and diabetes control among overweight patients with type 2 dabetes mellitus:  a 1-year prospective randomized intervention studyDiabetes, Obesity and Metabolism, 12 (2010): 204-209.

Esposito, Katherine, et al.  Effects of a Mediterranean-style diet on the need for antihyperglycemic drug therapy in patients with newly diagnosed type 2 diabetesAnnals of Internal Medicine, 151 (2009): 306-314.

2 Comments

Filed under Carbohydrate, coronary heart disease, Fat in Diet, Glycemic Index and Load, Mediterranean Diet, olive oil

Is Olive Oil Less Healthy When Used for Cooking?

Cooking doesn’t destroy much of olive oil’s healthy properties, according to registered dietitian Karen Collins in a recent guest post at CalorieLab.

I’ve been wondering about this since olive oil plays such a prominent role in the Advanced Mediterranean and Ketogenic Mediterranean Diets.  I use room-temperature olive oil on my salads and vegetables, but also use it  to sauté vegetables, eggs, and meat. 

Olive oil is the major fat in the traditional Mediterranean diet.  It has heart-healthy and perhaps anti-cancer action related to monounsaturated fat and phenolic compounds that have antioxidant and anti-inflammatory properties.

Steve Parker, M.D.

1 Comment

Filed under Health Benefits, Mediterranean Diet

Olive Oil in Mediterranean Diet Linked to Lower Body Weight

MPj04332860000[1]

The source of virgin olive oil

The University of Navarra in Spain reported recently that a diet rich in virgin olive oil reduces body weight, especially in those genetically inclined to gain weight.  Over one thousand research particpants were placed on a  Mediterranean diet and monitored by lead researcher, Ph.D. candidate Cristina Razquin:

This consisted of a high intake of fruit and vegetables and of non-refined cereals and fish, and the use of virgin olive oil as the main source of fatty food. Moreover, a high intake of legumes and nuts is recommended.

We’ll have more details when the research is published in a peer-reviewed scientific journal.  Olive oil is a type of fat.  This finding of lower body weight on an olive 0il-rich Mediterranean diet run counter to the generally accepted idea that dietary fat causes body fat.  Lower body weight is linked to lower risk of diabetes.

Steve Parker, M.D.

Reference:  A diet rich in virgin olive oil reduces body weight, according to research by the University of Navarra.  Press release, August 3, 2009.

Comments Off on Olive Oil in Mediterranean Diet Linked to Lower Body Weight

Filed under Mediterranean Diet, Overweight and Obesity

My Ketogenic Mediterranean Diet: Day 37

MPj04327450000[1]Weight: 158.5 lb

Transgressions: none

Exercise: none

Comments

I eat a large salad once or twice daily, often dressed with Safeway Select “Olive Oil and Balsamic Dressing.”  Wouldn’t you think the this would be an olive oil vinaigrette?  The first ingredient listed on the bottle is vegetable oil (soybean oil, extra virgin olive oil).  Then water, balsamic vinegar, etc.  I assume it has more soybean oil than olive oil.  Could they just put a drop of olive oil in a serving and still call it “Olive Oil and Balsamic Dressing”?

Just an example to illustrate you don’t really know what you’re eating unless you fix it yourself.  Gotta admit the product is tasty, however!

I’ll look for another product with extra virgin olive oil as the primary ingredient.  Any suggestions?

Steve 

6 Comments

Filed under Uncategorized

My Ketogenic Mediterranean Diet: Day 13

MPj04327450000[1]Weight: 162.5

Transgressions: Ate a fancy salad my wife made me while I was asleep, with glazed walnuts, 1/4 apple, 6 grapes, lettuce, etc.  More carbs than usual, but not by much.  How could I turn her down?

Exercise: 30 minute brisk walk

Comments

If I don’t get my required 2-3 tbsp of daily olive oil in salad or cooking, I just drink it straight.

I just realized I’ve been putting 1% milk in my coffee, 2 cups a day.  Measured a milk serving as 1.5 fl oz per cup, totalling 6 g of digestible carbohydrate daily that I had been overlooking before.  Will start drinking coffee black and revise my Week 1 Recap carb total.

-Steve

Comments Off on My Ketogenic Mediterranean Diet: Day 13

Filed under My KMD Experience

My Ketogenic Mediterranean Diet: Day 3

BBE085Weight: 165 lb

Transgressions: none

Exercise: none

Comments

I don’t entirely believe that 5 lb (2.3 kg) loss in 24 hours.  Scale may not be accurate.  If the loss is real, it couldn’t be all fat tissue.  Ketogenic diets supposedly cause lots of water loss, as discussed yesterday.  Wouldn’t be surprised if weight is up to 169 tomorrow.  Had to drink a tbsp of olive oil to stay compliant with diet yesterday (minimum of 2-3 tbsp olive oil/day).  Wife sautéd sugar snap peas (snow peas) and chicken breast for dinner today: simple and tasty.  She figured out that slow-cooking the cheaper cuts of beef softens it up nicely.  Later, will have a salad with canned albacore tuna, olive oil vinaigrette, some green olives, and avocado.

-Steve

Comments Off on My Ketogenic Mediterranean Diet: Day 3

Filed under My KMD Experience

Which Components of the Mediterranean Diet Prolong Life?

We're pro-life

We're pro-life

Researchers at Harvard and the University of Athens (Greece) report that the following specific components of the Mediterranean diet are associated with lower rates of death:

  • moderate ethanol (alcohol) consumption
  • low meat and meat product intake
  • high vegetable consumption
  • high fruit and nut consumption
  • high ratio of monounsaturated fat to saturated fat
  • high legume intake

Minimal, if any, contribution to mortality was noted with high cereal, low dairy, or high fish and seafood consumption. 

The researchers examined diet and mortality data from over 23,000 adult participants in the Greek portion of the European Prospective Investigation into Cancer and nutrition.  You’ll be hearing more about the EPIC study for many years.  Over an average follow-up of 8.5 years, 1,075 of participants died.  652 of these deaths were of participants in the lower half of Mediterranean diet adherence; 423 were in the upper half.

Alcohol intake in Greece is usually in the form of wine at mealtimes. 

The beneficial “high ratio of monounsaturated fat to saturated fat” stems from high consumption of olive oil and low intake of meat. 

It’s not clear if these findings apply to other nationalities or ethnic groups.  Other research papers have documented the health benefits of the Mediterranean diet in at least eight other countries over three continents. 

The researchers don’t reveal in this report the specific causes of death.  I expect those data, along with numbers on diabetes, stroke, and dementia, to be published in future articles, if not published already.  Prior Mediterranean diet studies indicate lower death rates from cardiovascular disease and cancer.   

Steve Parker, M.D.

Reference:  Trichopoulou, Antonia, et al.  Anatomy of health effects of the Mediterranean diet: Greek EPIC prospective cohort studyBritish Medical Journal, 338 (2009): b2337.  DOI: 10.1136/bmj.b2337.

Comments Off on Which Components of the Mediterranean Diet Prolong Life?

Filed under Alcohol, Health Benefits, Mediterranean Diet